Systematic Improvement of Parton Showers with Effective Theory
Abstract
We carry out a systematic classification and computation of next-to-leading order kinematic power corrections to the fully differential cross section in the parton shower. To do this we devise a map between ingredients in a parton shower and operators in a traditional effective field theory framework using a chain of soft-collinear effective theories. Our approach overcomes several difficulties including avoiding double counting and distinguishing approximations that are coordinate choices from true power corrections. Branching corrections can be classified as hard-scattering, that occur near the top of the shower, and jet-structure, that can occur at any point inside it. Hard-scattering corrections include matrix elements with additional hard partons, as well as power suppressed contributions to the branching for the leading jet. Jet-structure corrections require simultaneous consideration of potential 1 -> 2 and 1 -> 3 branchings. The interference structure induced by collinear terms with subleading powers remains localized in the shower.
Keywords
Cite
@article{arxiv.1007.0758,
title = {Systematic Improvement of Parton Showers with Effective Theory},
author = {Matthew Baumgart and Claudio Marcantonini and Iain W. Stewart},
journal= {arXiv preprint arXiv:1007.0758},
year = {2011}
}
Comments
54 pages, 24 figures, plus a few appendices. v2: included a parameter "eta" to account for energy loss, title improved, journal version